Currently the glassfish server plugin provides only an arbitrary text field to enter the path to java executable. The common consensus seems to be to provide a java platform customization tab (see eg. tomcat, jboss, weblogic).
As a side effect the glassfish server plugin does not provide any information about the java platform the server uses and this hinders the user experience when starting the server in profiling mode (eg. asking the user for valid java platform even though run/debug is working just fine).

Hmmm. we could add a java platform tab to the dialog when the java-ness of the IDE is activated. We would need to disable the text field when that happens.
This kind of change is fairly late in the 7.2 cycle....
Committing to Next for TM

Just out of curiosity - how can you install and enable the GF server support without turning on the Java Platform module? I tried to achieve that by downloading the PHP edition of NB and then installing the GF plugin. That resulted in the core of JavaEE/Java being sucked in and as a consequence the Java Platform module installed and activated.